Learning Japanese, which Pokemon game out of these two? 10 points!!!?

Mystery dungeon will most likely have repeated dialogue because you're pretty much doing the same thing over again so you'll probably end up remembering the words and how they're used in the sentences. Most of the game play doesn't really have dialogue though cause you're in dungeons a lot fighting and finding items.

Pokemon Ranger has more dialogue throughout the whole game while you're progressing through the story, explaining how to use your equipment and missions. It also offers a wider variety of dialogue to learn from taking side quests and interacting with other characters.